Amino acid uptake is strongly affected during exponential growth of Saccharomyces cerevisiae in 0.7 M NaCl medium.
Labelling of Saccharomyces cerevisiae grown in 0.7 M NaCl with 35S-methionine revealed a 5-6 fold lowering of the methionine incorporation into protein, which could not be attributed solely to the approximately 50% longer generation time of cells grown in 0.7 M NaCl. Subsequent studies of the high affinity methionine uptake system showed a strongly reduced uptake of methionine during growth in 0.7 M NaCl medium. This reduced uptake was shown to be strain-independent and caused mainly by an approximately 20-fold lowered maximum velocity (Vmax) of the transport system, while the substrate affinity (Km) displayed only a minor change. A salt-instigated reduction of uptake was furthermore demonstrated for the leucine and histidine high affinity uptake systems and also for a mixture of 15 different amino acids. We therefore suggest that the reduced amino acid uptake is a general phenomenon observed in salt-grown cells.
Norbeck
J
J
Department of General and Marine Microbiology, University of Göteborg, Sweden. Joakim.Norbeck@gmm.gu.se
Blomberg
A
A
D000596:Amino Acids / Q000378:metabolism; D001692:Biological Transport / Q000502:physiology; D002352:Carrier Proteins / Q000378:metabolism; D003470:Culture Media / Q000494:pharmacology; D007700:Kinetics; D008715:Methionine / Q000493:pharmacokinetics*; D009997:Osmotic Pressure; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*
D000596:Amino Acids; D002352:Carrier Proteins; D003470:Culture Media; D012965:Sodium Chloride; D008715:Methionine